I have recently subscribed to QuickBooks Online for A G H Financial Solutions L.L.C. As we are an accounting firm managing multiple client companies, we are interested

It sounds like you're looking to manage multiple client companies with QuickBooks Online. If that's the case, you can sign up to QuickBooks Online Accountant for free. This will let you access your clients’ financial records in real-time, share documents securely, and enjoy a bunch of other features as well. Since you mentioned you're already subscribed to QuickBooks, you can sign up directly on our website using your existing user ID and create an accountant firm. 
 

Once you’re all set up, check out these articles to help you get started with managing your QuickBooks Online Accountant and your clients:
 

• Get Started with Global QuickBooks Online Accountant
• Manage Your Clients
   

Feel free to reach out if you have any questions or need more help.